Zr compound films such as ZrN films, ZrB2 films and the like have been used for barrier films against diffusion of high melting point metal compounds used to form films in a process of manufacturing a semiconductor device. A Zr compound is promising for a conductive barrier film because of its low bulk resistivity of 10 μΩcm. In addition, it has been proposed to use a Zr compound for a conductive cap film, which is unnecessary to be eliminated, based on the property that its resistivity is extremely varied depending on the type of a base film.
In addition, a method has been proposed to form a ZrN film by a thermal chemical vapor deposition (CVD). However, this method needs to pay attention to high resistance due to residual carbon and generation of insulative compounds such as Zr3N4 and the like since a film formation temperature is above 300° C. or an alkylamino-based compound or the like is used as a raw material, which contains carbon.
On the other hand, regarding the formation of a ZrB2 film, a technique has been proposed for forming a film using a CVD or an atomic layer deposition (ALD) by using Zr(BH4)4 as a raw material and introducing H2 gas or NH3 gas excited by plasma into a processing container.
However, a conventional technique is known that requires a remote plasma equipment to introduce atomic H or the like into the processing container. This makes a configuration of a film forming apparatus complicated, which is inappropriate for industrial applicability in a semiconductor process. In addition, in the above technique, a B/Zr ratio in the ZrB2 film formed using a thermal CVD with Zr(BH4)4 used as a raw material becomes excessive, which may result in a deterioration of film quality.